Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 191518
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
1118 AM EDT Sat Aug 19 2017

.SYNOPSIS...
Isolated to scattered thunderstorms will likely develop during
the mid afternoon and early evening across the northwest
Alleghenies and the central ridge and valley region before
dissipating tonight. Fair weather is expected Sunday and Monday,
with temperatures turning warmer and more humid into early next
week. Thunderstorms are probable on Tuesday followed by a
refreshingly cooler and dry second half of the week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Fog has dissipated over central PA. GOES-16 satellite trends
show cumulus developing to the east of weakening early morning
convection near the PA/OH border.

There is a strong signal in the hires convective-allowing models
(CAMs) for scattered thunderstorms to develop across the
northwest Alleghenies into the central ridge and valley region
this afternoon into the early evening - in advance of a
seasonably strong shortwave and diffuse surface front. Modest
instability and deep layer shear combined with relatively cool
mid level temperatures will support risk for isolated strong to
severe storms with locally damaging winds and marginally severe
hail. SPC maintained marginal risk outlook for today with the
13z update. The most likely timing for storms based on the
latest CAMs is toward later in the afternoon/early evening
timeframe ~ 4 to 8pm.

Expect convection to diminish in intensity/coverage as it
pushes into east-central PA/Susquehanna Valley region during
the late evening. Dry wx expected after midnight as high
pressure builds over the area. Models are showing low stratus
potential over the Alleghenies with weak upslope flow and low
level moisture trapped under subsidence inversion. Patchy
fog is also likely in the usual spots across the central
valleys.

&&

.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
The quick exit off to the east of the sharp shortwave will lead
to a bright day Sunday with a light breeze and comfortable
humidity.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
The medium range models are all in good agreement on bringing a
renewed surge of heat and humidity into the area to start the
new work week. Highs Monday and Tuesday will be well up into the
80s with some southern locations possibly touching 90 Tuesday.

There`s decent agreement in having a vigorous cold front pass
through the region Tuesday night into early Wednesday. That will
be the best chance for organized precipitation coming up next
week with widespread showers and thunderstorms likely starting
late Tuesday, lasting into the overnight before tapering off as
scattered showers Wednesday.

The remainder of the week into the weekend looks to be cool and
mainly dry as a sprawling high moves slowly eastward out of
southern Canada.

&&

.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
Restrictions this morning have improved to VFR which will
prevail into the afternoon. Local thunderstorm impacts are
possible mainly between 20-24Z. Clearing skies fcst tonight
with models suggesting potential for IFR stratus/fog mainly
over the western 1/2 of the airspace. Early morning
restrictions will improve to VFR by 15Z.

.OUTLOOK...

Sun-Mon...Mainly VFR, but restrictions in morning fog.
Tue...Thunderstorm impacts likely.
Wed...Improving conditions.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$
SYNOPSIS...La Corte/Steinbugl
NEAR TERM...La Corte/Steinbugl
SHORT TERM...La Corte/Steinbugl
LONG TERM...La Corte
AVIATION...Martin/Steinbugl


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